Friction losses for water flowing in non-circular ducts PublicDeposited

Descriptions

Friction factors were measured for water flowing in ducts made
up of two rods held between two flat plates. Three rod diameters of
0.50, 1.00 and 1.50 inches were used. The spacings between rods
varied from 0.0 to 0.32 inch. It was found that the concept of
hydraulic diameter was adequate to correlate data and equations of the
forms corresponding the Blasius power form and the Nikuradse-Von-Karman logarithmic form were obtained. The friction factor
values are almost 40% less than values of circular tubes at the same
Reynolds number. The correlations obtained have a maximum of 5%
variation over 215 experimental data points. Analysis of data also
showed that 2-8% of the cross-sectional area of duct can be considered
laminar flow and the remainder to be in turbulent flow. This
division of two regions is nearly constant at an angle of 20-30° which
is the angle subtended by the laminar portion of the stream at the
center of a rod. This angle is defined in Figure 7. Reynolds number
range from 2,000 to 30,000.